Though he received a no-decision, Clay Buchholz pitched like a winner, allowing one run over eight innings.

He shot for the moon with a pair of three-run homers in Wednesday night’s rout of the White Sox.

But Thursday night, in the finale of this four-game series, Cody Ross reached for the stars, clobbering another three-run homer and lifting the Red Sox to a dramatic 3-1 walkoff victory before a euphoric Fenway Park crowd of 38,413, the largest turnout of the season.

“He loves that situation, he loves being in the big spotlight,’’ manager Bobby Valentine said of his right fielder, who hit out of the No. 5 spot. “He went deep, three runs, we win, and that’s about as much fun as guys have had in a long time. Good feeling.’’

After his contributions in Wednesday’s 10-1 romp, Ross was struck by a sense of déjà vu when he came up with one out in the bottom of the ninth. He drove a 1-and-1 pitch from righthanded reliever Addison Reed into the Green Monster seats to erase a 1-0 deficit.

“It’s an incredible feeling,’’ Ross said after the third walkoff homer of his career and his 16th homer of the season. “It’s something that you can’t really describe with words. The emotions that are going through your body, you’re just trying to take it all in and trying not to rush it and remember it, because you don’t have very many opportunities to do that.’’

The Red Sox were handcuffed by 23-year-old lefthander Jose Quintana, who threw eight scoreless innings, allowing five hits while extricating himself from a bases-loaded jam in the seventh. The Sox started their winning rally against lefthanded reliever Matt Thornton.

Carl Crawford led it off with a single to right. Dustin Pedroia, playing in his first game since coming off the disabled list (strained right thumb), then slapped a grounder to third that wiped out Crawford at second on the force out. Pedroia, however, beat the relay to first.

Adrian Gonzalez then sent a single to right. White Sox manager Robin Ventura summoned Reed to face Ross, who had Pedroia at second and pinch runner Nick Punto at first.

“The first pitch I think was away, ball maybe,’’ Ross said. “Second pitch was down and in, really good pitch, and in that situation, with a runner on second, I’m just looking for a pitch to handle and get really good wood on it and try to create something. Fortunately, he threw me a fastball in.’’

As soon as the ball left the barrel of his bat, “I got this real excited feeling,’’ Ross said.

“Then I had flashbacks to [Wednesday] night when I hit the same ball that hit the wall [for a double in the sixth inning],” he said. “I was thinking, ‘OK, even if it hits the wall, Punto’s fast enough to score from first, and we’ll still win, 2-1.’ That was all going through my mind. Then I saw it land and [Alex] Ochoa [the first base coach] was there giving me a high-five.’’

Alfredo Aceves got his first win of the season by throwing a scoreless ninth in relief of starter Clay Buchholz, who held the White Sox to one run on six hits and one walk over eight innings while striking out six. It was his second start since coming off the disabled list July 14 (esophagitis).

“When he’s going, he’s as tough as anybody in the league,’’ Ross said of Buchholz. “He’s proven that. And he’s starting to get that confidence and we need that.’’

The Red Sox desperately needed their starter to keep the White Sox in check with Quintana keeping them at bay. Making his 10th major league start and first against the Red Sox, Quintana retired his first eight batters before Pedro Ciriaco, the Red Sox’ designated hitter du jour, tripled to center.

Quintana, however, extinguished the threat by ringing up his second strikeout of the inning, retiring Jacoby Ellsbury on a foul tip.

The White Sox took a 1-0 lead in the fourth when designated hitter Adam Dunn drew a leadoff walk, Buchholz’s first and only of the game. After he hoofed it to third on Paul Konerko’s sharp single to right, Dunn scored when Alex Rios lofted a sacrifice fly to right. Buchholz buckled down and struck out A.J. Pierzynski and induced Dayan Viciedo into a fielder’s choice.

After retiring 11 straight batters, Quintana gave up consecutive singles in the seventh by Pedroia, Gonzalez, and Ross to load the bases for Will Middlebrooks.

Quintana dealt a fastball that Middlebrooks slapped toward the middle. But shortstop Alexei Ramirez made a diving stab to his left and started a 6-4-3 double play that left the Red Sox empty-handed.

“It was nice to come out yesterday and score 10 runs and then we look up today in the ninth and we don’t have any runs,’’ Ross said. “You’d think after [Wednesday] night, we’d feed off that and just keep going, but they shut us down and we ended up coming back.’’

When the Sox signed Ross, most didn’t anticipate his impact: 16 homers and 50 RBIs.

“I remember the excitement in [GM Ben Cherington’s] voice when he said ‘We got a player who’s really going to help us,’ ” Valentine said. “As an [ESPN] announcer, I did some of Cody’s postseason games in San Francisco. I loved his smile, I loved his game, I loved his energy. What’s there not to love, especially tonight, huh?